<?php
class Person {
    public static $name = '张三';
    public $age = 10;
    public static function test() {
        echo self::$name . self::test2();
    }

    public static function test2() {
        echo 'abcd';
    }
}

//$p = new Person();
////echo $p->name;
//$p->test();
//echo Person::$name;

Person::test(); // 推荐使用